265 results about "Acetoxy group" patented technology

The present disclosure provides methods of manufacturing psilocybin and crystalline psilocybin via a reaction of psilocin and tetrabenzylpyrophosphate in the presence of lithium chloride complex Grignard reagent, which is followed by hydrogenation. Methods of producing psilocin from 4-hydroxyindole or 4-acetoxyindole are also provided.

The invention discloses a synthetic method of glabridin with optical purity, which comprises the following steps: by taking (R)-3-acetoxyl-2-(2, 4-dimethoxyphenyl) propanol and 2-isopentenyl resorcinol as raw materials, carrying out Mitsunobu reaction to obtain a key intermediate compound I, then carrying out hydrolysis and iodination to obtain an intermediate compound II, and then carrying out cyclization to obtain the glabridin with optical purity. Reducing and removing a protecting group to obtain glabridin. By introducing the isopentene side chain, the reaction activity of an olefin functional group is reserved, a key site is provided for subsequent cyclization conversion, the precise spatial configuration of the product is ensured, and finally glabridin with optical purity is prepared. The method is short in route, low in cost, mild in reaction condition and suitable for industrial production.

The present invention relates to the technical field of liquid crystal polymer modification, and particularly relates to a crosslinked liquid crystal polymer, a preparation method thereof and an application. The crosslinked liquid crystal polymer is formed by crosslinking an aromatic liquid crystal polyester and a polyfunctional polyester oligomer in a mass ratio of 100:(0.4 - 5); the repeating unit of the polyfunctional polyester oligomer has the structure shown in formula (I) or formula (II), wherein the end groups of R1 - R6 are each independently selected from a carboxyl group and an acetoxy group, and at least one of R1, R2 and R3 in formula (I) or at least one of R4, R5 and R6 in formula (II), and its molecular chain contains a -C(O)-Ar-C(O)- link; Ar represents an aromatic ring. The crosslinked liquid crystal polymer has the advantages of high modulus and high temperature resistance, and can also maintain good flexibility and film-forming property, and thus can be formed into a diaphragm by diaphragm forming to prepare a diaphragm material. #imgabs0#

The invention discloses a preparation method of 4-(acetoxy) phenyl-2-methyl-2-acrylate, which takes mild DMAP as a reaction catalyst, produced phenolic ester is not easy to hydrolyze due to weak alkalinity, and the dripping speed and the reaction temperature are controlled at the same time, so that simultaneous esterification of two hydroxyls of hydroquinone can be effectively avoided, and the yield of 4-(acetoxy) phenyl-2-methyl-2-acrylate is improved. And generation of by-products can be reduced. According to the method, the ethyl acetate and petroleum ether mixed solvent with the ratio of 1: 2 is adopted for recrystallization, hot filtration operation is carried out, insoluble substances are by-products, solids separated out after filtrate is cooled are target products, operation is simple, high-yield target product powder solids can be directly obtained, and the purity can reach 80% or above. The method is simple and rapid in process, short in production period, low in production cost, high in total yield of target products and suitable for industrial production.

The invention discloses a powder treating agent, two-component heat-conducting gel as well as a preparation method and application of the two-component heat-conducting gel. The powder treating agent is prepared by sequentially carrying out hydrosilylation reaction on D4H cyclotetrasiloxane, vinyl silane, olefin and phenyl vinyl silicone oil. Wherein the structural formula of the vinyl silane is Vi-Si-(OR1) 3, and OR1 is a methoxy group, an ethyoxyl group, a formyloxy group or an acetoxyl group; the structural formula of the olefin is # imgabs0 # 20 > = q > = 8; and Vi is vinyl. According to the powder treating agent disclosed by the invention, a polysiloxane polymer and a phenyl group are introduced, so that the powder treating agent has excellent temperature resistance, is not degraded and volatilized under the condition of long-time high-temperature aging, ensures that hardness and thermal resistance are not obviously increased and has excellent thermal stability, and when the powder treating agent is used in heat-conducting gel, the thermal stability of the heat-conducting gel is effectively improved, and the service life of the heat-conducting gel is prolonged. And the service life and the period of the electronic component are prolonged.

The transparent deacidification type long-acting mildew-proof silicone sealant is prepared from the following components in parts by mass: 80 to 110 parts of basic polymer, 15 to 25 parts of plasticizer, 6 to 9 parts of cross-linking agent, 10 to 15 parts of filler, 0.05 to 0.2 part of mildew preventive, 1 to 2 parts of tackifier and 0.05 to 0.2 part of catalyst, the cross-linking agent is any one or a combination of more of methyl triacetoxysilane, ethyl triacetoxysilane, propyl triacetoxysilane, methyl tris (2-ethyl acetoxygroup) silane or methyl tris (benzoyloxy) silane; and the cross-linking agent is any one or a combination of more of methyl triacetoxysilane, ethyl triacetoxysilane, propyl triacetoxysilane, methyl tris (benzoyloxy) silane. Through the design of the sealant formula, the sealant with excellent comprehensive performance can be obtained, the curing speed is high, the bonding performance is good, long-acting mildew prevention is achieved, and the use scene of the sealant is widened.

The application discloses a PAG bonding type photosensitive photoresist resin and a preparation method and application thereof. The photoresist resin is as follows: formula. The PAG bonding type resin is prepared through the following reaction process: 1) performing a RAFT polymerization reaction on p-acetoxystyrene, p-styrene sulfonamide trifluoromethyl potassium salt and a RAFT chain transfer agent under the action of an initiator to obtain an intermediate I, 2) performing a hydrolysis reaction on the intermediate I to obtain an intermediate II, 3) performing a protection group introduction reaction on the intermediate II and di-tert-butyl dicarbonate to obtain an intermediate III; and 4) performing an ion exchange reaction on the intermediate III and triphenylsulfonium bromide. The application realizes the bonding of the PAG into the resin skeleton, and improves the problems of poor compatibility between the PAG and the resin, phase separation, uneven distribution of the PAG and the like. Therefore, the photoresist prepared from the resin has the photo-generated acid bound by the polymer main chain and limited diffusion, the resolution is improved, and the photoetching effect is excellent.

The invention discloses a recoverable easy-to-rinse low-density label and a recovery method thereof. The recoverable easy-to-rinse low-density label is prepared by performing surface modification on a low-density thermal shrinkage film through a surface modifier; the density of the low-density heat shrinkage film is less than 0.96 g / cm < 3 >; the surface modifier is prepared by carrying out a reaction on ethyl orthosilicate, N-(2-N-benzyl aminoethyl)-3-amino propyl trimethoxy silane and acetoxyethyl trimethoxy silane by virtue of a sol-gel method. The preparation method comprises the following steps: carrying out a reaction on ethyl orthosilicate, N-(2-N-benzyl aminoethyl)-3-amino propyl trimethoxy silane and acetoxyethyl trimethoxy silane by virtue of a sol-gel method; according to the label subjected to surface modification, the adhesion effect and stability of printing ink on the surface of the label can be improved, meanwhile, rapid separation can be achieved through simple flotation in the recycling process, the printing ink on the label can be effectively rinsed in rinsing liquid, the rinsing effect of the printing ink is improved, and the service life of the label is prolonged. And therefore, impurity-free recycling of the label is realized.

The invention relates to the technical field of chemical intermediates, and particularly discloses a preparation method of a givelastat intermediate.According to the preparation method, an initiator compound 5 can be synthesized by adopting cheap 2-hydroxy-6-naphthoic acid (CAS: 16712-64-4, 141 yuan / kg), and the preparation method is different from a method in the prior art. A gemvelastat intermediate compound 4 is synthesized from a compound 5 through a three-step reaction, compared with the prior art, the yield is high, industrial amplification production is more facilitated, in the process of synthesizing a compound 6 from the compound 5, acetonitrile can be adopted as a cyanide source in a reaction system, activated hydroxyl is subjected to a coupling reaction, and the yield is high. In the process of synthesizing a compound 6 from a compound 7 instead of a traditional metal cyanide, or in the process of synthesizing a compound 6 from another compound 5, a cheap cuprous cyanide and cuprous iodide system is adopted for a coupling reaction, and in the process of synthesizing a compound 4 from a compound 7, an acetic acid and sodium triacetoxyborohydride reaction system is adopted, so that the compound 6 is synthesized. And the important intermediate of the givelastat can be obtained with high yield.

The invention relates to the field of pharmacy, and provides a crystal form B of a compound cis-(+)-5-[(2-dimethylamino) ethyl]-2-(4-methoxyphenyl)-3-acetoxy-2, 3-dihydro-1, 5-benzothiaza # imgabs0 #-4 (5H)-ketone hydrochloride, which can meet the pharmaceutical requirements of convenient production, processing, transportation, storage and the like. The invention also relates to a preparation method of the crystal form B of the compound, a raw material medicine containing the crystal form B, a composition containing the crystal form B and application of the crystal form B in preparation of medicines for treating angina pectoris, hypertension, coronary heart disease and / or arrhythmia.

The invention discloses a method for preparing biphenol type high-heat-resistance liquid crystal polyester through melt coupling solid-phase polycondensation, which comprises the following steps: synthesizing a liquid crystal polyester prepolymer with specific logarithmic viscosity and melting point from p-acetoxybenzoic acid monomer, 4, 4-diacetoxybiphenyl and terephthalic acid according to different molar ratios; placing the crushed and dried prepolymer particles in a solid phase polycondensation device, accurately controlling the time, temperature and nitrogen flow rate of the polycondensation reaction to obtain the biphenol type high-heat-resistance liquid crystal polyester, and taking out the biphenol type high-heat-resistance liquid crystal polyester for DSC (differential scanning calorimetry) test. In the preparation process of the prepolymer, the molar percentage of the biphenol monomer is effectively regulated and controlled to prepare the prepolymer with proper logarithmic viscosity and high melting point, and the influence of different monomer proportions on the melting point of the polymer is researched; the solid-phase polycondensation time required for obtaining the biphenol type high-heat-resistance polymer is shortened by crushing the prepolymer into particles with different diameters, so that the solid-phase polycondensation efficiency is improved.

The invention relates to a core-shell polyacrylamide nano flocculant as well as a preparation method and application thereof, the flocculant is of a core-shell structure, the shell is a water-soluble polyacrylamide polymer, and the core is cross-linked poly (p-hydroxystyrene); the preparation method comprises the following steps: preparing a poly (p-tert-butoxystyrene-b-polyacrylate) block polymer or a poly (4-acetoxystyrene-b-polyacrylate) block polymer; carrying out hydrolysis and self-assembly on poly (p-tert-butoxystyrene) or poly (4-acetoxystyrene) on the block polymer at the same time in the presence of a trifluoroacetic acid hydrolysis reagent by utilizing a modification induced self-assembly process, and carrying out in-situ crosslinking on poly (p-hydroxystyrene) obtained by hydrolysis by using formaldehyde; and in the presence of a 1, 5, 7-triazabicyclo [4.4. 0] decene-5-ene catalyst, modifying the polyacrylate block by using an amination reagent to prepare the flocculant. Compared with the prior art, the flocculant provided by the invention has the advantages of controllable morphology, stable cross-linkable property and the like.

The invention discloses a method for preparing methyltriacetoxysilane from acetic anhydride-containing acetyl chloride distillation tailings, and relates to the technical field of organic silicon synthesis, the method comprises the following steps: adding methyl trichlorosilane and acetic anhydride-containing acetyl chloride distillation tailings into a reaction kettle, stirring and heating; after a total reflux condition is reached, maintaining total reflux for a period of time, and then starting to collect acetyl chloride; continuously heating until the collection of acetyl chloride is completed, stopping heating, and when the temperature of the kettle is reduced to room temperature, heating again and starting vacuum negative pressure; when the kettle temperature reaches a set value, stopping heating, stopping stirring, and closing vacuum negative pressure; and after the kettle temperature is reduced to room temperature, adding pretreated activated carbon, carrying out decoloration reaction, and carrying out suction filtration after the reaction is completed, thereby obtaining the product. According to the method, a large amount of acetic anhydride in the acetyl chloride distillation tailings is used as a raw material and directly reacts with methyl trichlorosilane to prepare methyltriacetoxysilane, and the quality of the obtained product is remarkably higher than that of a product prepared by a normal process.

The present invention provides a hair dyeing method which comprises a step 1 and a step 2 in this order, and does not comprise a step for rinsing hair between the step 1 and the step 2, and comprises a step for rinsing hair after the step 2: step 1: a step for applying an agent A to hair, the agent A having a pH value of 8-11 and containing the following components (a1) and (a2): (a1) a compound represented by general formula (1) or a salt thereof; the dashed line represents the presence or absence of a pi bond, R1 represents a hydroxyl group or an acetoxy group, R2 represents a hydrogen atom or-COOR (R represents a hydrogen atom, a methyl group or an ethyl group), and R3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group); (a2) an alkaline agent; step 2: A step for applying agent B to hair, said agent B containing the following component (b): (b) alkali metal salt or alkaline earth metal salt selected from among organic acid salts or inorganic salts having 6 or less carbon atoms # imgabs0 #

The present invention discloses a catalyst for synthesizing 1,4-diacetoxy-2-butene, its preparation method and application. The catalyst includes a carrier, a main active metal, and a co-active metal; the main active metal includes Pd, the co-active metal includes Te and / or Sn, and the carrier is silica modified with carbon quantum dots. The catalyst provided by the present invention is used in the synthesis reaction of 1,4-diacetoxy-2-butene, and has the characteristics of high selectivity of 1,4-diacetoxy-2-butene and few by-products.

The present invention discloses an instant-adhesive strong-tough wet tissue tape and a preparation method thereof. The preparation of the instant-adhesive strong-tough wet tissue tape comprises the following steps: S1, reacting 3,4-dihydroxyphenylacetic acid with glycidyl methacrylate to synthesize 2-(2-(3,4-dihydroxyphenyl)acetoxy)-3-hydroxypropyl methacrylate; S2, dissolving chitosan in an acrylic acid aqueous solution, then adding 2-(2-(3,4-dihydroxyphenyl)acetoxy)-3-hydroxypropyl methacrylate and a photoinitiator to obtain a mixed solution; S3, applying the mixed solution to the surface of a polymer film treated with a plasma cleaner, and then curing under ultraviolet light to obtain the instant-adhesive strong-tough wet tissue tape. This invention designs and synthesizes novel catechol compounds with long alkyl side chains and uses them to manufacture an instantly adhesive, strong, and resilient wet tissue tape. This tape is thin, flexible, and optically transparent, conforming to various substrates and allowing visual inspection of the substrate's state. Prior to use, the tape is dry and non-sticky, but upon contact with water or blood, it rapidly bonds to wet biological tissue. The tape exhibits exceptionally strong interfacial toughness and adhesion strength to wet biological tissue, far exceeding existing commercial adhesives and some other wet tissue adhesives. Therefore, the instantly adhesive, strong, and resilient wet tissue tape can be used for wound closure and hemostasis.

The invention relates to the field of pharmacy, and provides a crystal form B of a compound cis-(+)-5-[(2-dimethylamino) ethyl]-2-(4-methoxyphenyl)-3-acetoxy-2, 3-dihydro-1, 5-benzothiaza-4 (5H)-one hydrochloride, which can meet the pharmaceutical requirements of convenient production, processing, transportation, storage and the like. The invention also relates to a preparation method of the crystal form B of the compound, a raw material medicine containing the crystal form B, a composition containing the crystal form B and application of the crystal form B in preparation of medicines for treating angina pectoris, hypertension, coronary heart disease and / or arrhythmia.

This invention provides a compound for recognizing chiral amino alcohols, a fluorescent probe, its preparation method, and its application. Naphthol and sodium hydride are weighed and dissolved separately in ultra-dry tetrahydrofuran, mixed, and then reacted with bromomethyl methyl ether. The mixture is extracted with ethyl acetate, and the organic phases are combined to obtain product (R)-1. This product is dissolved in ultra-dry tetrahydrofuran, and n-butyllithium is added. The reaction system changes from colorless to brown, and the reaction is allowed to return to room temperature. Ultra-dry N,N-dimethylformamide solution is then added, and the reaction is quenched by adding saturated ammonium chloride solution under ice-water bath conditions. The product is then extracted with ethyl acetate to obtain product (R)-2. Product (R)-2 is dissolved in a mixed solvent of tetrahydrofuran and anhydrous methanol, and sodium triacetoxyborohydride is added. The product is then extracted with ethyl acetate to obtain reduced product (R)-3. Product (R)-3 is dissolved in a mixed solvent of dichloromethane and anhydrous ethanol, and concentrated hydrochloric acid is added. After the reaction is complete, the reaction is quenched with sodium bicarbonate, and then extracted with dichloromethane to finally obtain compound (R)-4, which recognizes chiral amino alcohols.

The invention provides S-fluoroalkyl substituted amino acid, polypeptide and a preparation method of the S-fluoroalkyl substituted amino acid, and belongs to the technical field of fluorinated amino acid. The chemical structural formula of the compound is shown in the specification. Wherein Ar is 4-phenyl phenyl, 4-acetyl phenyl, 4-methoxycarbonyl phenyl, 4-acetoxyphenyl, 4-cyano phenyl, 4-(N, N-dicarboxamide) phenyl, 4-(N, N-dicarboxamide) phenyl, 4-(N, N-dicarboxamide) phenyl, 4-(N, N-dicarboxamide) phenyl, 4-(N, N- Ar'is phenyl, 4-iodophenyl, 4-bromophenyl, 3-methoxycarbonyl phenyl, 2-naphthyl or 3-thienyl, and R1 and R2 are methyl or H. According to the preparation method of the S-fluoroalkyl substituted amino acid and polypeptide, the adopted raw materials are low in cost, simple and easy to obtain, glassware cannot be corroded like other methods, and the tedious and functionalization steps are omitted in the preparation method.

The invention provides a synthesis method of L-acetoxypropionyl chloride, and belongs to the field of medical intermediates and fine chemical engineering. The preparation method comprises the following steps: mixing L-lactic acid and acetyl chloride for first reaction; then adding trichlorotoluene and a catalyst to carry out a second reaction; and then rectifying and separating to obtain the product L-acetoxypropionyl chloride. According to the method, two raw materials react to generate two products, no sulfur dioxide or acidic mixed waste gas is generated, the utilization rate of the raw materials reaches 100% theoretically, and the method completely conforms to an environment-friendly and pollution-free green process. The safety of the used trichlorotoluene is far higher than that of thionyl chloride and phosgene, the reaction is mild, the reaction speed can be controlled by controlling the temperature and the input amount of the catalyst, the production operation is relatively safe, and the purity of the prepared L-acetoxypropionyl chloride product is greater than 99%, and the yield is greater than 90%.

The invention discloses (E)-1, 4-diether olefin and a preparation method thereof, and the (E)-1, 4-diether olefin is obtained by using 1, 3-diene as a raw material and carrying out electrochemical reaction in the presence of an electrolyte and a solvent, wherein the 1, 2, 4-trimethyl-1, 3- The structural formula of the 1, 3-diene is as follows: R1 is phenyl, p-fluorophenyl, p-chlorphenyl, p-bromophenyl, p-methylphenyl, p-methoxyphenyl, p-trifluoromethylphenyl, p-trifluoromethoxyphenyl, p-acetoxyphenyl, p-methyl formate phenyl, p-cyanophenyl, p-pinacol borate phenyl, p-phenylphenyl, o-oxybenzyl phenyl and o-methoxyphenyl; r1 is one of 1, 2-naphthyl; the solvent is a mixed solvent containing methanol. The preparation method of (E)-1, 4-diether olefin has high E-selectivity and 1, 4-selectivity, and an electro-catalysis mode is adopted, so that the use of a stoichiometric toxic, expensive or dangerous oxidant is avoided.

Poly (catechol-styrene) (PCS) is a novel material having a variety of industrial and biomedical uses. For example, PCS acts as a binder that acts in a humid or underwater environment, and thus can be used in biomedical applications. The present disclosure provides a method of forming a poly (catechol-styrene) polymer. The method includes the step of polymerizing 3, 4-diacetoxystyrene and styrene in an emulsion polymerization to form a poly (3, 4-diacetoxystyrene-co-styrene) polymer. The polymer has acetate groups deprotected from an alcohol, thereby forming a poly (catechol-styrene) polymer. The poly (catechol-styrene) polymer has improved strength at a higher molecular weight.

The present technology relates to a process useful for preparing the crystalline (S)-1,1-bis(4-fluorophenyl)propan-2-yl (3-acetoxy-4-methoxypicolinoate)-L-alaninate compound (I), which comprises distilling a mixture, which comprises distilling a mixture containing an aprotic organic solvent, a protic organic solvent, the compound (I), and a seed crystal of the compound (I), or which comprises distilling a mixture containing an aprotic organic solvent and the compound (I) and crystallizing the compound (I) by preparing a second mixture containing a protic organic solvent, the compound (I), and a seed crystal of the compound (I). The process disclosed herein describes a more stable and storage-compatible preparation of the compound (I). Preparations of the compound (I) having fewer (trace) impurities are also disclosed.

The invention discloses a method and a system for preparing a 4-AA medical intermediate through continuous flow ozone oxidation. The method comprises the following steps: continuously introducing a raw material solution containing (3R)-3-((R)-1-((tert-butyldimethylsilyl) oxy) ethyl)-1-(4-methoxyphenyl)-4-oxo azetidine-2-yl acetate and a gas containing ozone into a microreactor for reaction; after the reaction liquid is subjected to reduction quenching, the (3R, 4R) 4-acetoxyl-3-[R-(tert-butyldimethylsiloxy) ethyl]-2-azetidinone is obtained. On one hand, the reaction time is shortened from the hour level to the minute level, and the production efficiency is remarkably improved; and on the other hand, the reaction temperature is increased to 10-30 DEG C from deep cooling, so that the refrigeration energy consumption and the equipment requirement are greatly reduced. According to the invention, local peroxidation is fundamentally avoided, byproducts are obviously reduced, the product purity is improved, the method is suitable for continuous operation, the reaction process is controllable, and the method is safe and reliable.

The invention discloses bio-based polyamide with low water absorption and a preparation method thereof, and belongs to the technical field of polyamide preparation. The bio-based polyamide with the low water absorption rate is prepared from the following components in parts by weight: 30 to 50 parts of pentamethylene diamine, 15 to 30 parts of sebacic acid, 5 to 12 parts of citric acid, 5 to 10 parts of hexamethylenediamine, 2 to 5 parts of a hydrophobic auxiliary agent and 1 to 5 parts of a modified high-temperature-resistant additive, the hydrophobic additive is prepared from acetoxybenzoic acid, nonadecanoic acid, m-dimethoxybenzene, trifluoroacetic anhydride and methyl tert-butyl ether as raw materials, and the modified high-temperature-resistant additive is prepared from o-phenylenediamine, chloroacetic acid, vanillin, benzoyl bromide and thiourea as raw materials. The bio-based polyamide prepared from the substances has low water absorption and excellent thermal stability.

The invention relates to the technical field of photoresist film-forming resin preparation, and discloses KrF photoresist film-forming resin and a preparation method and application thereof.The preparation method comprises the steps that 4-acetoxystyrene monomers or 4-acetoxystyrene monomers and other comonomers are filtered and then added into a dispersing agent, stirring is conducted, and the KrF photoresist film-forming resin is obtained; adding an organic photocatalyst and a chain transfer agent, and mixing to obtain a mixed solution; introducing inert gas into the mixed solution, irradiating the mixed solution under the condition of visible light, and reacting to obtain a polymer solution; and separating out the polymerization liquid, drying, adding ammonia water or a hydrazine hydrate solution, and reacting to obtain the KrF photoresist film-forming resin of which the molecular weight distribution is less than 1.2. By adopting a photo-initiation mode, on one hand, the energy consumption in the polymerization process can be reduced, and the reaction conditions are mild; on the other hand, the preparation process of the polymer can be well controlled in time and space, and the inter-batch stability is ensured.

The invention belongs to the technical field of resveratrol synthesis, and particularly relates to a preparation method of resveratrol and application of resveratrol in meat preservation. The method comprises the following steps: taking 3, 5-dimethoxybenzoic acid as a raw material, and carrying out acylation reaction to obtain 3, 5-dimethoxybenzoyl chloride. Then reacting with p-acetoxystyrene to generate 3, 3 '-dihydroxy-3, 3'-dihydroxy-3 The preparation method comprises the following steps: taking 1, 5-dimethoxy-4 '-acetoxystilbene as a raw material, hydrolyzing and demethylating to obtain resveratrol, and preparing resveratrol lipid nanoparticle suspension by taking resveratrol, a ZIF-8 / chitosan compound, compound lipid, cholesterol, epsilon-polylysine, ascorbyl palmitate and phosphate buffer saline as raw materials. High load and controlled release of resveratrol are achieved, and the problems that resveratrol is poor in water solubility and prone to oxidation are solved.

The invention relates to a preparation method of an iopamidol chiral side chain. Specifically, the invention provides a preparation method of (S)-2-acetoxypropionyl chloride, which comprises the following steps: (1) mixing L-lactic acid and ethanol, adding toluene, vinyl acetate, onion pseudomonas lipase and a 3A molecular sieve, reacting, filtering, and concentrating the filtrate under reduced pressure to obtain (S)-2-acetoxypropionic acid; and (2) adding the (S)-2-acetoxypropionic acid prepared in the step (1) into a mixed solution of thionyl chloride and pyridine, stirring for reaction, heating for reflux reaction, and concentrating the obtained reaction solution under reduced pressure to obtain the (S)-2-acetoxypropionyl chloride. The (S)-2-acetoxypropionyl chloride prepared by the method disclosed by the invention has the advantages of excellent purity and yield, mild reaction conditions and simple operation, is beneficial to industrial production, and is further beneficial to preparation of high-purity and high-yield iopamidol as an intermediate, so that the application value of iopamidol is improved.

The invention discloses a method for synthesizing 4-acetoxy-2-methylbutyraldehyde. 4-hydroxy-2-butanone is used as a starting raw material, and condensation, hydrolysis, and esterification (or esterification, condensation, and hydrolysis) reactions are performed to prepare the 4-acetoxy-2-methylbutyraldehyde. The condensation is performed under the catalytic action of an alkaline substance and a halogenated acetate is used as one of the reaction raw materials. The esterification uses acetic acid and / or acetic anhydride as one of the reaction raw materials. The reaction process is highly safe and easy to operate, and the yield is high. In particular, the raw materials are simple and readily available, and no noble metal catalyst is required in the reaction process, thereby significantly reducing the preparation cost. Compared with the prior art, the method is more suitable for large-scale industrial production.

The invention discloses a synthesis method of m-acetoxystyrene, which is characterized by comprising the following steps: adding m-hydroxybenzaldehyde, vinyl ethyl ether and trifluoroacetic acid into an organic solvent A, and reacting in an inert gas atmosphere to obtain a reaction solution; dropwise adding the reaction solution into a Wittig reagent, carrying out a reaction, and carrying out post-treatment, so as to obtain 1-(1-ethyoxyl ethyoxyl)-3-vinyl benzene; the Wittig reagent is prepared by dispersing methyl triphenyl phosphorus bromide and sodium methoxide in an organic solvent B; the preparation method comprises the following steps: adding 1-(1-ethoxyethoxy)-3-vinylbenzene, an acid solution and an acetylation reagent into a solvent to react, and preparing m-acetoxystyrene after the reaction. The method is simple in process step, mild and controllable in reaction condition, high in equipment universality, low in comprehensive production cost, capable of effectively inhibiting side reactions and improving the product quality, suitable for industrial production and high in practicability.